<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>16_Promise封装Ajax.html</title>
  </head>

  <body>
    <script>
      //接口地质:https://api.apiopen.top/getJoke

      const p = new Promise(function (resolve, reject) {
        //1.创建对象
        const xhr = new XMLHttpRequest();
        //2.初始化
        xhr.open("get", "https://api.apiopen.top/getJoke");
        //3.发送
        xhr.send();
        //4.绑定事件，处理相应结果
        xhr.onreadystatechange = function () {
          //判断
          if (xhr.readyState === 4) {
            //判断响应状态码
            if (xhr.status >= 200 && xhr.status < 300) {
              //表示成功
              resolve(xhr.response);
            } else {
              //如果失败
              reject(xhr.status);
            }
          }
        };
      });

      //指定回调
      p.then(
        function (value) {
          console.log(value);
        },
        function (reason) {
          console.error(reason);
        }
      );
    </script>
  </body>
</html>
